Big Sandstone Climbing Holds 4 Pack by Three Ball Climbing 4 Big Climbing Grips Made with rigid rock-like polyurethane. Incut Sandstone crimp rails, excellent for steep overhanging walls. Not recommended for contoured concrete walls. Steel Installation hardware for indoor walls included (bolts + T-nuts + Wrench) For outdoor walls give us a call and we can upgrade your package to Stainless Steel Hardware for $8 480-334-4646